As one type of a drive apparatus for a vehicle, there is a known configuration of a drive apparatus for a hybrid vehicle having a motor as a motive power source for the vehicle, in which an output voltage of a battery is boosted by a boost converter and the boosted voltage is used for driving the motor. For example, Japanese Patent Laying-Open No. 2003-134606 (hereinafter referred to as Patent Document 1) discloses a drive apparatus for a hybrid vehicle having a boost converter including a reactor as a component.
Generally, a reactor is configured by a core formed by a magnetic body and a coil wound around the core to ensure inductance. In such a configuration, the core generates heat in accordance with the electromagnetic energy conversion in the reactor, and the coil generates heat by Joule heat of the passing current. It is concerned that the voltage converting efficiency of the boost converter may be reduced by an increase in the temperature of the reactor due to such heat generation. Accordingly, a reactor heat dissipation mechanism is required.
As one example, Japanese Patent Laying-Open No. 2002-217040 (hereinafter referred to as Patent Document 2) discloses a configuration where a heat dissipation fin formed by a heat transfer plate is provided to the outer surface of a core (iron core) in a stationary induction electric device including a reactor.
Reduction of vehicle-installed components in size is a common problem to be solved for vehicles of every type. As to a hybrid vehicle, Japanese Patent Laying-Open No. 2004-343845 (hereinafter Patent Document 3) discloses a technique of reducing a drive apparatus in size by storing and integrating an inverter and a motor in one case.
However, in the heat dissipation mechanism for the reactor (stationary induction electric device) disclosed by Patent Document 2, the heat transfer plate for dissipating heat having the fin is additionally provided to the outer surface of the core. Therefore, the reactor becomes great in size. Accordingly, there is a problem in applying it to a boost converter as a component of a drive apparatus for a vehicle, of which adaptability to vehicle installation is weighed particularly heavily.
As to the configuration of integrating the motor and the electric circuitry group (inverter) for driving the motor disclosed by Patent Document 3, the existence of a boost converter is not particularly discussed. That is, Patent Document 3 is not aware of the problem of how to achieve both the efficient arrangement of a reactor and the ensured cooling performance, in such an integrated configuration.